Merge time machine backups

Yesterday I moved my external HD from the USB port on my MBP to my new Airport Extreme USB port. When I restarted Time Machine, it started a new backup of the whole machine. So, now I have a backup that goes from when I bought the MBP to yesterday and another backup from yesterday forward.

To access the old backup I have to dismount the HD from the AE, connect it to the MBP USB and manually look for files I need. Then reinstall the HD on the AE.